// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_APPCACHE_APPCACHE_URL_REQUEST_JOB_H_
#define CONTENT_BROWSER_APPCACHE_APPCACHE_URL_REQUEST_JOB_H_

#include <stdint.h>

#include <string>

#include "base/callback.h"
#include "base/memory/weak_ptr.h"
#include "content/browser/appcache/appcache_entry.h"
#include "content/browser/appcache/appcache_executable_handler.h"
#include "content/browser/appcache/appcache_response.h"
#include "content/browser/appcache/appcache_storage.h"
#include "content/common/content_export.h"
#include "net/http/http_byte_range.h"
#include "net/url_request/url_request_job.h"

namespace net {
class GrowableIOBuffer;
};

namespace content {
class AppCacheHost;
class AppCacheRequestHandlerTest;
class AppCacheURLRequestJobTest;

// A net::URLRequestJob derivative that knows how to return a response stored
// in the appcache.
class CONTENT_EXPORT AppCacheURLRequestJob
    : public net::URLRequestJob,
      public AppCacheStorage::Delegate {
public:
    // Callback that will be invoked before the request is restarted. The caller
    // can use this opportunity to grab state from the AppCacheURLRequestJob to
    // determine how it should behave when the request is restarted.
    using OnPrepareToRestartCallback = base::Closure;

    AppCacheURLRequestJob(net::URLRequest* request,
        net::NetworkDelegate* network_delegate,
        AppCacheStorage* storage,
        AppCacheHost* host,
        bool is_main_resource,
        const OnPrepareToRestartCallback& restart_callback_);

    ~AppCacheURLRequestJob() override;

    // Informs the job of what response it should deliver. Only one of these
    // methods should be called, and only once per job. A job will sit idle and
    // wait indefinitely until one of the deliver methods is called.
    void DeliverAppCachedResponse(const GURL& manifest_url,
        int64_t cache_id,
        const AppCacheEntry& entry,
        bool is_fallback);
    void DeliverNetworkResponse();
    void DeliverErrorResponse();

    bool is_waiting() const
    {
        return delivery_type_ == AWAITING_DELIVERY_ORDERS;
    }

    bool is_delivering_appcache_response() const
    {
        return delivery_type_ == APPCACHED_DELIVERY;
    }

    bool is_delivering_network_response() const
    {
        return delivery_type_ == NETWORK_DELIVERY;
    }

    bool is_delivering_error_response() const
    {
        return delivery_type_ == ERROR_DELIVERY;
    }

    // Accessors for the info about the appcached response, if any,
    // that this job has been instructed to deliver. These are only
    // valid to call if is_delivering_appcache_response.
    const GURL& manifest_url() const { return manifest_url_; }
    int64_t cache_id() const { return cache_id_; }
    const AppCacheEntry& entry() const { return entry_; }

    // net::URLRequestJob's Kill method is made public so the users of this
    // class in the appcache namespace can call it.
    void Kill() override;

    // Returns true if the job has been started by the net library.
    bool has_been_started() const
    {
        return has_been_started_;
    }

    // Returns true if the job has been killed.
    bool has_been_killed() const
    {
        return has_been_killed_;
    }

    // Returns true if the cache entry was not found in the disk cache.
    bool cache_entry_not_found() const
    {
        return cache_entry_not_found_;
    }

private:
    friend class AppCacheRequestHandlerTest;
    friend class AppCacheURLRequestJobTest;

    // Friend so it can get a weak pointer.
    friend class AppCacheRequestHandler;

    enum DeliveryType {
        AWAITING_DELIVERY_ORDERS,
        APPCACHED_DELIVERY,
        NETWORK_DELIVERY,
        ERROR_DELIVERY
    };

    base::WeakPtr<AppCacheURLRequestJob> GetWeakPtr();

    // Returns true if one of the Deliver methods has been called.
    bool has_delivery_orders() const
    {
        return !is_waiting();
    }

    void MaybeBeginDelivery();
    void BeginDelivery();

    // For executable response handling.
    void BeginExecutableHandlerDelivery();
    void OnExecutableSourceLoaded(int result);
    void InvokeExecutableHandler(AppCacheExecutableHandler* handler);
    void OnExecutableResponseCallback(
        const AppCacheExecutableHandler::Response& response);
    void BeginErrorDelivery(const char* message);

    // AppCacheStorage::Delegate methods
    void OnResponseInfoLoaded(AppCacheResponseInfo* response_info,
        int64_t response_id) override;
    void OnCacheLoaded(AppCache* cache, int64_t cache_id) override;

    const net::HttpResponseInfo* http_info() const;
    bool is_range_request() const { return range_requested_.IsValid(); }
    void SetupRangeResponse();

    // AppCacheResponseReader completion callback
    void OnReadComplete(int result);

    // net::URLRequestJob methods, see url_request_job.h for doc comments
    void Start() override;
    net::LoadState GetLoadState() const override;
    bool GetCharset(std::string* charset) override;
    void GetResponseInfo(net::HttpResponseInfo* info) override;
    int ReadRawData(net::IOBuffer* buf, int buf_size) override;
    net::HostPortPair GetSocketAddress() const override;

    // Sets extra request headers for Job types that support request headers.
    // This is how we get informed of range-requests.
    void SetExtraRequestHeaders(const net::HttpRequestHeaders& headers) override;

    // FilterContext methods
    bool GetMimeType(std::string* mime_type) const override;
    int GetResponseCode() const override;

    // Invokes |prepare_to_restart_callback_| and then calls
    // net::URLRequestJob::NotifyRestartRequired.
    void NotifyRestartRequired();

    AppCacheHost* host_;
    AppCacheStorage* storage_;
    base::TimeTicks start_time_tick_;
    bool has_been_started_;
    bool has_been_killed_;
    DeliveryType delivery_type_;
    GURL manifest_url_;
    int64_t cache_id_;
    AppCacheEntry entry_;
    bool is_fallback_;
    bool is_main_resource_; // Used for histogram logging.
    bool cache_entry_not_found_;
    scoped_refptr<AppCacheResponseInfo> info_;
    scoped_refptr<net::GrowableIOBuffer> handler_source_buffer_;
    std::unique_ptr<AppCacheResponseReader> handler_source_reader_;
    net::HttpByteRange range_requested_;
    std::unique_ptr<net::HttpResponseInfo> range_response_info_;
    std::unique_ptr<AppCacheResponseReader> reader_;
    scoped_refptr<AppCache> cache_;
    scoped_refptr<AppCacheGroup> group_;
    const OnPrepareToRestartCallback on_prepare_to_restart_callback_;
    base::WeakPtrFactory<AppCacheURLRequestJob> weak_factory_;
};

} // namespace content

#endif // CONTENT_BROWSER_APPCACHE_APPCACHE_URL_REQUEST_JOB_H_
